Branched aliphatic primary alcohols, especially those having long carbon chains, have found use in many applications such as surfactants, solvents, wetting agents, solubilizing agents, emulsifiers, or as an intermediates for making derivatives such as esters and ethers that can be used as surfactants, solvents, wetting agents, solubilizing agents, emulsifiers, and lubricant base stocks or additives.
A specific type of branched aliphatic alcohols are Guerbet alcohols, which are beta-branched primary alcohols having the following general structure:
where R1 and R2 can be any hydrocarbyl group, preferably alkyl groups such as linear alkyl groups. Guerbet alcohols and derivatives thereof, such as esters thereof, have found use as lubricant base stocks. Guerbet alcohols can be produced by Guerbet reaction, in which two primary alcohol molecules condense to produce a beta-branched primary alcohol molecule and water.
Recently, industrial interests in gamma-branched alcohols having structures similar to Guerbet alcohols as follows have grown:
where R1 and R2 can be any hydrocarbyl group. Such gamma-branched alcohols cannot be produced via two molecules of primary alcohols.
U.S. Pat. No. 8,383,869 B2 discloses a process for making such gamma-branched alcohols from a terminal olefin including a first step of producing a vinylidene olefin dimer of the terminal olefin, followed by hydroformylation of the vinylidene olefin dimer. However, this patent teaches that in the hydroformylation process, multiple alcohol isomers will be produced. Because the isomers have the same molecular weight and similar molecular structure, it would be very difficult to produce one gamma-branched alcohol at high purity. JP2005-298443A discloses a similar process for making gamma-branched alcohols from alpha-olefin. While a high purity gamma-branched alcohol was reportedly produced in an example in this patent publication, the purity still has room for improvement. In addition, the overall yield of the gamma-branched alcohol product from the terminal olefin as disclosed in JP2005-298443A has room for improvement as well.
A high-purity gamma-alcohol product can be far more useful than a mixture of multiple alcohols having different molecular structures. This is especially true where the gamma-branched alcohol is used as a feed to produce a derivative thereof, and a high purity of the derivative is desired for its end application.
Thus, there is a need for a high purity gamma-branched alcohol products and a process for making high-purity gamma-branched alcohol products with a high yield.
This disclosure satisfy this and other needs.